Low Bar
 

Is your team planning to go under the low bar?

Re: Low Bar
 

I am not surprised that most/all teams are saying they plan to go under the limbo bar.

The problem will be that about a week from ship date (bag date, whatever), teams will start to discover that their robot won't be able to scale the castle as they had planned or won't be able to open the Sally Port as planned or won't be able to shoot into the high goal as planned and still be able to limbo.

Then comes the hard decisions. Do they keep the limbo and just not do those things they had planned or do they add some feature to their robot that allows the skill but disallows the limbo?

I could be wrong but I think at best we'll have 50% limbo bots once you exclude robots that have no other skills beyond just being able to limbo.

Callin' 'em as I sees 'em.

Dr. Joe J.

Re: Low Bar
 

I agree with Joe, teams will probably get to crunch time and have to decide whether it is still worth going under the low bar or using one of their other mechanisms.



<sidestory> Joe, my Dad (Patrick who works in Tech Org at iRobot) and I were talking about you and your thoughts on the competition at literally the same moment you posted your reply. Crazy right? Go iRobot!</sidestory>

Re: Low Bar
 

Yup, we decided to not try to put any mechanisms on our robot, aside from a simple ball collector/shooter that will fit under 15" at the center, 12" at the ends. The shooter might hit the high goal. It will hit the low goal.

If we get ambitious, we might think about adding another mechanism...but so far, no one on the team has presented any feasible ideas for how to do the other parts of the game.

Re: Low Bar
 

We are going under the low bar, and after doing the math, our original design to hang will not be strong enough. We will probably end up removing that part of the robot and worry about the shooter. We designed a shooter that can shoot 16 feet (atleast), and consistently make it in.

Re: Low Bar
 

For those who are planning on going underneath the low bar, are you considering scaling the tower? If so, how important compared to other objectives do you consider having the ability to do both? Currently, are robot will be capable of going underneath the low bar easily, however we're unsure if we would like to scale the tower as well (partially due to time too).

Re: Low Bar
 

As week 3 ended our team has went under the low bar and several of the defenses. We have current plans for several prototypes that could also scale the tower. We have set a priority to fine tune our shooter and defenses. But will be a tight fit but we do have a spot to scale the tower.

Re: Low Bar
 

The low bar is one defense you can get relatively easily with a short height robot. It's also kind of the path back to get another boulder. We think it's kind of important, since it can speed up your cycle time, and help you get enough defenses and score enough boulders to possibly get you two ranking points. Scaling is ten points, and it could be an easy ten points if you're clever enough to make a good scaler....but we haven't figured out how yet, and really see the other parts of the game as being more important to do quickly.

It will be interesting to see how this all plays out...

Re: Low Bar
 

These short robots are also light. A removable scaling mechanism should be doable for many and still be under 120lbs.

Re: Low Bar
 

We are building a low bot that will scale, shoot H/L goal and cross all defenses, in theory. We'll see week 1 if it all works, I think it will. Plus we have an awesome auto planned

Re: Low Bar
 

We already almost had this with Robot in 3 Days--late Monday night, the Team Cockamamie robot sprouted a new piece to lower the Cheval de Frise or raise the portcullis. All of a sudden, the low bar became verrrrrrry tricky to manage, usually with a little bumping. Teams had better beware.

Re: Low Bar
 

Can those robots going under the low bar still:

-Scale?
-Shoot high?
-cross all defenses (except maybe C because no one seems to care)?
-get a 2 boulder autonomous?
-all those answers at the same time?

That is where it gets interesting! ;)

Re: Low Bar
 

cross all defences and get a 2 boulder autonomous (which I think is almost impossible without crossing the middle line) isn't about the height of the robot in my opinion.
I think that shooting high is a bit harder, but still lots of teams will do it.
the main problem will be scaling, it is very hard to put almost 2 meters of climbing mechanism into 40 cm robot (sorry for metric system lol), especially if you want to shoot high and scale the tower.
you will see the best teams do it all, but I think that it will be 20 teams max.

Re: Low Bar
 

As always, we started wanting to do everything. Scaling went first. Having the low bar available for the go-to boulder cycle was far more important. Note that we must be in a certain configuration (not starting configuration) to make the low bar. It is a configuration we will naturally have after loading and before launching a boulder, so it shouldn't slow us down.

Edit: I realize now that this is misleading. Our primary design goal is to be a sapper bot (knock out defenses), but we also recognize that the only "unlimited" points in the game come from scoring boulders in the tower. As such, we have as a close second requirement to be able to score in the high goal, preferably over a tall defending robot, which (as a low bar robot) means a high, relatively slow launch angle. After working through a drive train design (weeks 2 and 3 mostly) this is where most of our skull work is going. Pickups are a well enough understood question that we are designing them to also work the category A defenses (portcullis and cheval de frise).

Re: Low Bar
 

That is good in my opinion because if it is a conistent shooter and other teams are less geared toward shooting in the high goal but can scale and break defenses you will have a good matchup.

Re: Low Bar
 

2 ball autonomous seems much harder than the 20 point for stacking 2 yellow totes last year and that a 1 out of 30-40 ish skill last year (meaning 1 team out of 30-40 could reliably accomplish that task in a match). I suppose that 2 ball auton is closer to a 1 out of 100 ish skill meaning at most 30 to 40 teams in the world will be able to do this reliably. And as I type that, I don't believe it. No Sagi34 is right. more like a 1 out of 200 ish skill for 20 teams max.

Dr. Joe J.

Re: Low Bar
 

its easier than you think in theory, whether we pull it off is another story. I think many teams will attempt it as its 10-20 extra points if you score 2 or 3 balls in HG. Seems to me there is extra time that teams will not want to waste. I would say 1 in 50 teams will pull it off. About 1 successful per competition. I no way is it impossible as there are fixed points on the field for all necessary steps in achieving it.

10 extra points 2 ball auto = 2 HG tele points (extra 12.5% weaken)
20 extra points 3 ball auto = 4 HG tele points (extra 25% weaken)

Since it matters teams will try.

Re: Low Bar
 

Even then, i expect it to be able to be consistently accomplished by <5 teams, if at all. It just seems to be a task that requires insane accuracy, and requires ridiculously precise measurements, with a less than 5" margin of error (depending on how your intake works), and then being able to score twice with the right precision will be hard.

Re: Low Bar
 

True but a 2-3 ball auto is orders of magnitude harder than a defense of a 2-3 ball auto. Example, knocking the balls off the center line to anywhere but where the team that is doing the 2-3 ball auto wants them. A multi ball auto might help you capture the tower during quals but I'm not convinced that it secures a regional/championship win once teams can plan out defenses for it.

Re: Low Bar
 

Teams cannot defend in Auto without reprogramming the spy bot and highly risk a foul impeding crossing. As for midline shenanigans that means that bot is not scoring either. Not likely I'm saying.

I really don't see the advantage to not Scoring in auto yourself and attempting to prevent team X from doing their multi ball auto the mid line rule and the not prevent crossing rule make that highly unlikely to succeed.

Plus the way defenses are laid out they are on opposite sides so main auto action is opposite.

I guess it could happen however that seems very unlikely. But who knows?

Re: Low Bar
 

I hear you, Boltman. I definitely see the value. But, in the end, I'm with you, 3175student17.

I just think this is a tougher hill to climb than most teams that attempt it will be able to pull off. Many will try. Few will succeed.


Dr. Joe J.

Re: Low Bar
 

But not impossible. We have seen over and over teams do the "impossible" so I am saying it'll be more common than the way it seems. Many teams will want to max out the 15 seconds with scoring plays. I have seen more than 5 teams out of 4000 pull stunts like that off every year I have watched. When you get right down to it its easy if you have precision and speed. Its hard no doubt and I 'm sure many including us may fail. Many will try and some will pull it off.

Re: Low Bar
 

First, the spy bot is on your offensive side of the field and has nothing to do with defending multi ball autos. 2nd hitting two balls out of the way takes far less time then is needed to score in auto, they aren't mutually exclusive. A 1 or 2 ball lead on the tower coming out of auto is a huge advantage which is why high level teams will attempt that very hard challenge. If a team starts consistently making 2-3 auto balls it is clearly beneficial for an opposite alliance in eliminations to try to get to those balls first and prevent their opponents from scoring them. Wasn't it better for 1114 to try and defend 254's three ball auto in 2014 instead of scoring a high goal themselves.

Re: Low Bar
 

How are you planning on knocking balls in auto without crossing the mid-line and avoiding the high chance of a foul?

Re: Low Bar
 

How are teams planning to collect balls without getting foul? It seems a lot easier to just hit a ball then it does to intake it. Pretty sure it can be done with a pneumatic cylinder and a couple sticks.

Re: Low Bar
 

Perhaps I suspect intake to be easier.

Re: Low Bar
 

Anything involving the center line involves a ridiculous amount of accuracy, so I suppose it may be possible that you're right. That being said, it's a general rule that screwing something up is significantly easier than doing it, and I see no reason to suspect that's not the case here.

Re: Low Bar
 

I'm pretty surprised, and just a little worried, by how many teams are responding "yes" to this poll. I say all this as part of a team that, after much deliberation, decided to go for it, but I'm worried that there are a lot of teams out there who are not fully thinking through the rather dramatic implications of designing for the low bar, and the actual strategic value of it to the average team.

I think that there are a lot of FRC game tasks, or even just general robot characteristics, which teams do not attempt or prioritize every year simply because somebody told them "trying to do everything is bad, simple is good" rather than out of a tangible, well thought out reason that it's going to be difficult for the team to pull off, or because of a valid trade-off which improves performance elsewhere. Shifters, for example. I have a hard time seeing how choosing one bulletproof, battle-proven COTs gearbox over another bulletproof, battle-proven COTs gearbox makes a robot appreciably simpler, or quicker to put together. Last year, the classic case was canburglers. The vast majority of FIRST teams dismissed this task as "too hard," only to have teams that didn't see it this way rapidly retrofit their robots to steal cans during lunch. This year, I expect to see teams fail to meet their potential in this way in regards to scaling. It's an easy task to dismiss, but also an easy thing to add after the fact (look at the WCP MCC, for example). The common thread is, it can be achieved through an "auxiliary" mechanism, something that can just be slapped on top of a robot without affecting the rest of it that much. And it's pretty close to a "binary" task; unlike something like shooting where there will be a huge spectrum of performance with gains to be made by optimization at every level, you either scale or you don't, and there isn't much to be gained by spending a huge amount of time optimizing how quickly you can do it. I would argue that some of the defenses also fall under the category of tasks more teams will avoid based on philosophy than sound engineering analysis.

The low bar is not one of these tasks. It is the opposite of these tasks.

The ability to do the low bar is immensely integral to a robot's design. It affects every single element of it, and disqualifies a number of otherwise viable designs and approaches.

The low bar takes practically every archetypical design from the previous game to which you could effectively say "build team XYZ's robot from that year," Rebound Rumble, and throws them out the window.

The low bar will make your electronics team cry.

The low bar has a direct and dramatic impact on the effectiveness of every single subsystem of your robot. Instead of releasing boulders from four feet up, you're either releasing them from one foot, or adding in systems you didn't need without the low bar to make up the difference. Same with hanging, your reach distance changed dramatically.

The low bar also has its advantages. It's one more defense that you're guaranteed to be able to breach, taking the number of other defenses to design for down from 8 to 6, and possibly eliminating some of the ones which require dedicated mechanisms to achieve. It's also the most direct path to/from the secret passage, probably the fastest defense to cross, and provides you with an optimal cycle time.

I'm worried, however, that a lot of teams are overestimating the degree to which they'll be able to take advantage of this.

By doing the low bar, you have made being an accurate high goal shooter quite a bit harder. You have also made your shots easier to defend if you stick to a low release point. Teams doing the low bar are betting on being able to make up the difference through an increased cycle rate. The number of extra shots a team can expect to miss by building for the low bar is hard to estimate, but likely not trivial, and I would argue that for many teams and the rate at which we've seen that defenses like the rock wall and rough terrain can be crossed, it may be more effective to cycle over these with a taller robot. They are also betting on consistently being effective enough to take priority over their alliance partners in use of the low bar. If as many teams want to use it as people say there will be, there's going to be a traffic jam through the thing.

By doing the low bar, many teams are completely neglecting the possibility of scaling. These teams are demanding an extra two high goal boulders a match from their low bar cross, minimum.

For teams that have chosen to neglect the high goal, the picture is even more stark. A team would need to run five extra cycles per match to make up the difference from a scale, a task which becomes dramatically easier if you allow your robot to be tall. I would bet that most teams won't even average five a match, let alone five extra cycles due purely to low bar efficiency gains.

Many teams are designing to be "breaching specialists," crossing all 9 defense styles. This gives them an extra five points per match (and no change in RP), when compared to crossing 8. Scaling, or even a single high goal shot, does the same or better.

And that's all neglecting alliance partners. The low bar is weird, in that it can be reasonably expected that both the best and worst teams in FRC will be able to do it. For the best teams, the advantage in cycle time is clear, and it's integral to their strategies. For the teams that struggle to put a kitbot on the field, taking away an effective way to score points that you're given from the start would be a poor idea. For a team in the middle, it's a reasonable assumption that their partners will be able to take care of it, and may be actively hogging it for their own cycles.

I also think Dr. Joe is right. But teams should consider, which will be the more effective robots? The ones which were designed for five weeks to do the low bar, and then hastily had a few tall bits added? Or the ones which were designed from the beginning to take full advantage of their height?

Unless you expect to be able to take full advantage of the low bar's efficiency gains, it may be in many team's best interests to walk away from the extreme design tradeoffs that the low bar forces.

Re: Low Bar
 

Not sure how this thread about the Low Bar got sidetracked into a discussion about 2-ball auton, but here is my question:

How many teams have actually practiced going under the Low Bar WITH the cloth barrier in place? If you have, how would you say that it affects your ability to successfully cross the defense?

Also - it may have been stated elsewhere, but please note that the Team drawings of the field specify black iron pipe as the weight for the curtain, while the actual field will have an aluminum pipe - quite a difference in weight!

Re: Low Bar
 

[quote=Abrakadabra;1532940]Not sure how this thread about the Low Bar got sidetracked into a discussion about 2-ball auton, but here is my question:

How many teams have actually practiced going under the Low Bar WITH the cloth barrier in place? If you have, how would you say that it affects your ability to successfully cross the defense?

We have tried it. You need to make sure you don't have anything on the top of your robot for it to get caught on. It's very easy to get snagged. And you should have some time of roll bars or something else that accomplishes protecting the top of your robot. The bar/fabric will catch on the inside of your robot easily.

Re: Low Bar
 

Crossing defenses is not a problem with a good low bot and a HG shooter is definitely doable. The biggest "obstacles" are having to go further to touch the bar and scale (in endgame) also bumper placement. Everything else is doable. In fact its all doable and stay under 14.15" except during endgame.

It really boils down to can you design bumpers and a mechanism to scale. If teams are playing defense with a taller bot then you may be at a disadvantage however how many teams will play defense first off and secondly have a tall bot doing that sole task? I feel this will be a rare situation.

On the plus side limbo/low bot gives you pretty much automatic destruction of one defense or 25% of way to BREACH. Also it is likely lighter meaning less scaling (winching weight) issues.

I see a well designed low bot as a better choice than a well designed high bot for the sole reason it can cross a defense the High bot cannot ever in every match. All other things balance out. So well designed LB > well designed HB with all else being equal IMO

The only thing High Bot brings is defense possibility and possibly easier engineering solutions (crossing, goals and scaling) and bumper placement IMO and it seems other teams opinion according to the poll.

I think we will see more low/limbo bots than high bots this year from both less experienced and moderate to top end teams. Look at FRC champions lots of low bots through history they are prevalent.

Re: Low Bar
 

I agree with most of the assessments above... However, I do see being short enough to go under the low bar as being a very important aspect of this game.

* A robot hoping to advance out of District/Regionals has to be able to score points, even when allied with inept partners. There are two primary ways to do this: damaging defenses and scoring boulders.

* If a bot is designed to primarily damage defenses, being low is almost mandatory - Being short allows to you easily damage one of the defenses with no manipulators required (or even a fancy drive train).

* If a bot is designed primarily to score boulders, its design must consider from where it will acquire the boulders to score. The most reliable source will be its own secret passage - to which the most efficient path is under the low bar.

Though, being low isn't "mandatory" - its not like all three robots on an alliance will likely be able to share the path under the low bar to the secret passage particularly well, being low doesn't prevent other options (such as going through a different defense to attain boulders in the neutral zone; picking up missed shots in one of the courtyards or sneaking into the opponents secret passage to swipe a loose boulder)....

Yes, we have s short robot.

Re: Low Bar
 

We are design for 14" did you see any issues with anything below that height when crossing in either direction?

Re: Low Bar
 

The results of this poll are terrifying.

Re: Low Bar
 

We built for 15 7/8", and we were just scraping; 15 1/2" probably would've done it for that robot. Your mileage may vary based on wheel placement and angle of attack. (I drove the robot for the reveal video, and I had better luck coming in at a slight angle than straight on.)

Re: Low Bar
 

When I see this pole I get the feeling that plenty of teams have come to the relatively same conclusion and that is that the consistency of the low bar out weighs many other considerations when it comes to design. What I believe is that most teams say that "we'll go under the low bar and then will just try to drive over some of the other obstacles and that will be enough for us."

What I don't think that many people have realized is that this will in fact not be enough in terms of a productive and winning robot. The robot will need to do something else. And making the decisions to go under the low bar limits your options in terms of other implements. A good robot, wanting to under the low bar, will need to be either able to shoot into the high goal or climb the tower in order to have any kind of value in eliminations.

Re: Low Bar
 

Maybe. Or maybe the low bar robot will be able to get a lot of ranking points, by ensuring that the alliance will breach and capture, using the quickest and most reliable methods. Then they'll be the ones picking the alliance for eliminations.

It will be fun to watch what happens

Re: Low Bar
 

Thought 1: It's a poll on ChiefDelphi, so it's a small sample of a small sample.
Thought 2: It's a poll on ChiefDelphi at the end of week 3, so it's a small sample of a small sample whose sample could shrink even further by ship date. (I know 2815 planned to cross the center divider in 2012...right until about Thursday afternoon at Peachtree when we determined there was a frame member about 3/16" too low that we missed when designing.)

I think your list omits some ways teams can get into consideration at most events*, but I do agree on the core point: low bar alone doesn't hang your banner. What it takes to do so will depend on what the top teams at your event didn't do--because they'll need that in order to achieve the breach and capture points.

(Consider: A captured tower is worth at least 56 points in playoffs, before autonomous or high goals or scales. Really at least 66, since someone had to get balls across the defenses to do this. Viewed in isolation, a breach is 60 before autonomous. I figure you'll be able to win quite a few with a two-digit score from Week 0.5 until probably Week 2. After that, the phrase will be "breach and capture.")

*Championship? MSC? IRI? Those are not most events. Start scaling and hitting high goals.

Re: Low Bar
 

I would think this... However, it sounds like a LOT of folks are building short robots designed to cycle under the low bar and score boulders in one of the goals.... If there are not very many robots that can effectively traverse some of the other defenses, one of those could find itself at the top of the rankings as it will always be in preliminary matches with robots that compliment (instead of duplicate) its abilities....

Re: Low Bar
 

I think low bots fall into all categories and many who build them will be able to do all the defenses and still score goals and even scale . I is seemingly the easiest way to build a scoring kit bot for rookies, I'm pretty sure a majority of older team low bots will be very capable beyond the low bar given.

Remember all low bots can open the doors from behind too. So low gives you ability to destroy 1 and aid others on another defense every match.

In the end the poll results show an unwillingness to give up on a guaranteed scoring play and assisting on another at the bare minimum. High only helps in defense abilities due to height. But limbo bot may transform to high.

Re: Low Bar
 

Why?

Re: Low Bar
 

Why are folks assuming a robot that can limbo cannot cross other defenses as well? I understand, a little, why a low-rider may have trouble opening doors, lowering bridges or raising the portcullis but why would a low-rider have trouble with the other defenses? The low bar is not so low that it impacts wheel size choices. drive train choices etc.

Re: Low Bar
 

yup, we seem to be able to get over them with kit wheels on a slightly modified kit chassis.

Re: Low Bar
 

Why? We have room for a nice size electronics board, mounted near the top of the robot...easy access, etc. It took our electronics team about an hour to mount the parts and do the preliminary wiring.

Re: Low Bar
 

Our robot can fit under the Low Bar and, in theory, should be able to cross every defense by itself, so it's not impossible. However, this trade off my cause severe issues if we try to scale the tower as we'll have to develop something to grab the rung, which may prevent us from going under the Low Bar after it's added, which is also why we're considering it to be removable.

If you do go under the Low Bar, it's going to make doing other objectives harder, but not impossible.

Re: Low Bar
 

I agree (being low actually makes many of these easier). But many people are justifying their choice to do the low bar by saying "you don't even have to do anything special to the drivetrain!" Either you haven't done anything special to your drive, in which case you're going to have a hard time with the other defenses, or you have, in which case the point is moot, you've taken the time/effort to cross other defenses anyways.

I would assume for many reasons in my earlier post. There are going to be a lot of teams that will fail to meet their potential in other aspects of the game in pursuit of the low bar, and as a result, won't be able to gain enough from doing the low bar for it to be worth the design tradeoffs.

This was not our experience, and I know of many teams sharing in our pain. There are factors that don't apply to all teams (in our case, significant amounts of space dedicated to boulder pathways, and being unable to afford to do the whole robot on Talon SRXs). I've seen worse, but there will be a lot of cramped boards this year.

Re: Low Bar
 

I'm not Karthik, but from my experience in FIRST:

1. Teams often have trouble doing basic game piece manipulation. Throw in the low bar, and you'll have teams be even worse because now they add in the design constraint of going under the low bar.

2. Doing the low bar means you'll likely have to compromise on some other game objectives.

Re: Low Bar
 

I've just seen it as a design challenge so far: how do we fit all the stuff into a compact package? It's been challenging for our team but the process has been positive and productive. Having a low height constraint has the side benefit of preventing other problems (high COG). Hm.

Re: Low Bar
 

The shape that you need to be able to get under to limbo is surprisingly complicated. If you are not using CAD or some sort of to scale drawings, you are going to be one of those teams I discussed above, that THOUGHT they would go under the bar but don't in the end.

First of all you have to ask if you need to go under the bar in FWD and REV and from which side. The envelope changes significantly if you face your robot toward the opponent's tower or toward your own because (thanks FIRST) the bar is not in the middle of the outer works.

A lot depends on your wheel base and wheel diameters and such but (SPOILERS) there is a V out in front of (and behind of) your robot that is not even close to 14 inches from the "ground plane" (i.e. the plane that your robot drives on if it were a flat floor). I don't have the CAD pulled up but I think for our particular chassis parameters, the base of the V shaped "keep out zones" comes close to the top of our bumper.

SO... really if you have some boulder collector device you plan on folding out in front of your robot while it's doing the limbo, you really really really need to be sure that you can limbo in the real world not just in your minds.

Word to the wise.

Dr. Joe J.

P.S. Getting your boulder mechanism hooked on the limbo bar counts as a Tortuga. I'm just saying...

Re: Low Bar
 

Something people are forgetting is that if you have a low shooter, due to the nature of virtually no safe zones besides the outer works, all that a team has to do to block you is strap pool noodles onto a kit bot and your shooter is rendered useless. Even with the outer works safe zone, your shooter better be getting the ball to 54" tall before it leaves your frame perimeter or its getting blocked. My team was considering the low bar for the first week of build season and we ruled it out for that reason along with the difficulty of compacting all components of the robots in that small of footprint, because a team with my team's level of resources (3 mentors, two that are technical), building a good shooter that can do tasks other than the low bar is a much better option than forcing a design contstraint that causes more problems than it fixes.

Re: Low Bar
 

This is what I see the advantages and disadvantages of being against a defender.

Cons:
1. Your cycle time when shooting is increased. depending on the robot matchup (faster vs slower, taller vs shorter) this could be significant.
2. Your potential to challenge the tower for the extra point at the end of the match could be at risk.
3. You can have your boulder stolen from you in a race to pick up a deflected ball. This would be a significant time loss.

Pros:
1. Unless the defender leaves to accomplish tasks periodically it isn't contributing to its team's ability to meet the requirements to gain ranking points (barring W-L points).
2. A defender is scoring 0 boulders while defending. Assuming all robots have equal offensive scoring capabilities (a stretch, I know but for the sake of argument) a 3 robot offensive is still going to push out more points through goals unless said defender can impede the progress of more than one robot simultaneously and do it well. 2 unimpeded robots on the enemy alliance are not going to outscore 2 unimpeded robots on your alliance plus one impeded robot.

On that note, if anyone has some good footage of defensive robots impeding multiple robots during an FRC game where multiple robots can score at the same time (much like this year's challenge) I'm looking for them! I do think there will be some strong defenders and I need to convince the rest of my team they exist.

Now on the topic of "low robots will always be shut down by tall robots" I don't think that will be the case because:

1. You can close the distance between yourself and the tower where a robot can't maneuver in between yourself and the goal. Stopping you from getting to that point is difficult since the defender would need to give you enough space to start in their courtyard to not incur a foul when you are traversing the outer works.
2. Trajectory is key. If you arc your shot you can shoot over a tall robot. As long as you're not shooting from the front edge of your robot you have wiggle room to arc it.

Re: Low Bar
 

With one only defensive robot in your courtyard is hard committing that robot to defend against only one other robot really a good call?

Re: Low Bar
 

Yes, especially at events where accurate high goal shooters will not be found for second picks, and you can pick a blocking bot who can focus on one shooter on the opposing alliance, forcing them to have one decent/good shooter + one 'okay' shooter while your alliance can be scoring two decent/good bots' worth of shots. At IRI, DCMPs, and Championship, this is different, but you have to get to all of those before you can strategize for those levels of play.

Re: Low Bar
 

This is taking into account the ranking system this year correct?

Re: Low Bar
 

And a lot of people seem to be dismissing the natural 'safe zone' created by the batter and tower itself. Our thought process was 'why shoot from far away when I can drive right up to the tower, wedge ourselves on the ramp and take a close shot?' See 2014 robots that wedged themselves against the low goal and the corner of the field.

We are doing the low bar and so far haven't ran into any major issues. I think it's accessible to a lot of teams with a little planning, but it definitely requires some thought & testing to package everything well.

Re: Low Bar
 

Dr. Joe, unsurprisingly, speaks the truth. That measurement was right for us, but it may well not be for you. Plan accordingly!

Re: Low Bar
 

I can't speak for everyone, but I don't believe for a moment that being short prevents other options, but it does create some challenges with space and, therefore, potentially the number/type of other mechanisms... For instance, we decided to forgo all pneumatic systems.

I do think that if nearly all robots are short and specialize in going under the bar to retrieve balls from the secret passage that there will be room for robots that specialize in other aspects of the game to excel as they will likely have more complimentary alliances.

Re: Low Bar
 

We had decent success with that approach in 2014 and hope to do something similar this year.

I think there are some inherent advantages to being "compact" (generally synonymous with short) this year in addition to getting under the low bar. In fact, the low bar height is just a convenient target value for "compactness". This field is one big fatigue test rig. In order to survive and function the entire season, your robot will need to be robust. The fewer moving parts, deployable mechanisms, lanky appendages, etc., the better you will be after the umpteenth crossing of the Group B & D defenses. A robot that can collect a boulder, cross a defense, and shoot a high goal without moving anything in the shooter assembly is more likely to survive continued contact with this game. Shooting from the batter requires a bit more driving, but it is a semi-protected shot that can be aimed by driving into a couple of fixed field elements (the tower and the driver station wall). Being able to go under the low bar isn't critical to this approach, but it is a good fit.

Scaling the tower is another matter...

Re: Low Bar
 

Thanks, Did you scrape in both directions or just one direction?

Re: Low Bar
 

The difference is that you had squarish robots parkng in a squarish space. This year the park and shoot area is a trapezoid which will make it easier for defenders to turn you so you miss. That said, there are ways to minimize the defenders defense. Such as a turret shooter or a trapezoidal robot.

Speaking of which, has any team ever made a trapezoid robot?

Re: Low Bar
 

Depending on the width of your frame plus your bumper height, you could still square yourself up using the polycarbonate lane dividers on the batter. You just need to be able to shoot very close to the tower. See the attached picture.

Re: Low Bar
 

From that picture it still looks like a defnder could twist you around if they hit one of your back corners. Also the polycarbonate will flex some meaning you aren't in exactly the same position every time.

Re: Low Bar
 

Moreover, a robot that has been designed to fit under the low bar as a rigid swept volume may find that things work a bit differently at 10+ feet per second...and especially with bouncy wheels...

Re: Low Bar
 

This is a little off topic of the low bar but this diagram brings up an interesting point. If this robot is up on the batten scoring and a defensive robot parks perpendicular behind it and the offensive robot cannot push it out of the way is it still considered a pin? I imagine that teams may have trouble with traction due to the batten material.

I haven't seen an official pinning definition in the Q&A yet. Does it count as a pin to just park there and hold them if we don't initiate contact?

Re: Low Bar
 

I'd like to know this as well.

Re: Low Bar
 

We reconfigured the kit chassis to use pneumatic wheels and did lots of testing with it over the defenses with uneven terrain. Here it is crossing just an empty platform at roughly full speed with nothing in the way. We unintentionally flipped that drivetrain upside down just once, but it wasn't when going over the rock wall or moat... it was when we went full speed over an empty platform and tried to slow down at the end.

Crossing defenses is very dynamic, CAD doesn't really show whether a design will work or not. Adding pneumatic wheels just makes things even more unpredictable. We weren't at all happy with that 6wd pneumatic setup, we're doing something else.

Re: Low Bar
 

I just posted this question to the Q&A. We'll see what they say...

https://frc-qa.firstinspires.org/Que...sive-robot-par

Re: Low Bar
 

What about it were you unhappy with?

Re: Low Bar
 

Off topic, but why do people keep calling the Batter, Battens? Us the Batter similar to ship battens or something like that?

Perhaps using phone to post and spell check is helping out lol

Re: Low Bar
 

Planning yes but I see some weird things happening when we run the simulation.

Re: Low Bar
 

I'd be surprised if it wasn't pinning / trapping. Especially once the robot makes a move to leave that area.

Agree that the polycarbonate would flex some. It definitely isn't as nice as 2014's corner shot but we're hoping it'll be good enough.

Re: Low Bar
 

This!

Re: Low Bar
 

I not sure how good of a defensive strategy that is. The match is effectively 2 on 2, but the rest of the court is left wide open for the other robots to score. and if you are not clear of the court yard in the last 20 secs of the match, you risk big penalties.

Re: Low Bar
 

I'm not a ref or part of the GDC but my understanding is that pinning is defined as one robot not being able to move at all from a location.

Re: Low Bar
 

2 years ago, anything that prevented an opposing robot from moving away was considered pinning/trapping. Using the same definition, the situation described would be considered a pin.

Re: Low Bar
 

For reasons explained in the video. For one, you have a severe loss of control and precision going over the defenses when the drivetrain is doing nosedives across the defenses. It also wasn't that great at going over slowly. In short we weren't satisfied with going over defenses if we couldn't do it in a fast AND controlled manner so we opted not to go with a modified kitbot. Even if it meant sacrificing build time that could have went towards something else like the shooter. It seemed/still seems worth it since the drivetrain is literally half the game this year.

Re: Low Bar
 

Answered, and as most of us expected, will be pinning.